The steid whaur the ceety wis foondit haes been inhabitit bi the Motu-Koitabu fowk for centuries. The first European tae see it wis Caiptain John Moresby in 1873. It wis named in honour o his faither Admiral Sir Fairfax Moresby.

Awthou Port Moresby is surroondit bi Central Province, o whilk it is an aa the caipital, it isna pairt o that province, but forms the Naitional Caipital Destrict.